<!DOCTYPE html>

<html>
<script>

var result;

function success(keySystemAccess) {
  result = 'supported';
}

function failure(error) {
  result = error.name;
}

function isKeySystemSupported(keySystem) {
  // requestMediaKeySystemAccess() checks for video/mp4 support, so this
  // is only available if proprietary codecs are enabled.
  navigator
      .requestMediaKeySystemAccess(
          keySystem,
          [
            {
              videoCapabilities :
                  [ {contentType : 'video/mp4; codecs=avc1.4D000C'} ]
            }
          ])
      .then(success, failure);
}

function areProprietaryCodecsSupported() {
  var video = document.createElement('video');
  return video.canPlayType('video/mp4; codecs=avc1');
}

</script>
</html>
